Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

719
FXUS63 KLOT 061722
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1222 PM CDT Mon Apr 6 2026

.KEY MESSAGES...

- Low (<30%) chance for scattered snow showers near Lake
  Michigan tonight into early Tuesday.

- Sub-freezing temperatures expected tonight, but warmer
  conditions develop Wednesday and into the weekend.

- Brief chance for a light snow/rain mix Tuesday night.

- Periods of showers and storms are possible late in the week
  into next weekend.

&&

.DISCUSSION...
Issued at 239 AM CDT Mon Apr 6 2026

Early morning GOES vapor imagery shows a low-amplitude short
wave tracking quickly east-southeast across the western Great
Lakes region. At the surface, a cold frontal trough associated
with this wave extended from central Lake Michigan, southwest
into far southeastern IA as of 06Z. A cluster of showers (with a
couple of isolated lightning strikes noted over the past 1-2
hours) was noted ahead of the cold front, from La Salle county
to southern Lake Michigan and northwest Indiana. These showers
will exit the forecast area to the east during the predawn
hours, with the cold front following shortly behind them. Breezy
northwest winds gusting around 30 mph will usher in slightly
cooler temperatures today, resulting in highs from the mid-upper
40s along the IL/WI border to the mid-50s well south of I-80.
Sky cover will vary from partly to mostly cloudy (more clouds
likely north, more sun to the south).

Another sheared mid-level short wave is progged to transit the
upper Midwest this afternoon, which will send another
reinforcing, sharp lake-assisted cold front southward into the
area this evening. This will turn still-blustery winds more
north-northeast tonight, while also dropping temperatures into
the mid-20s to low-30s. There also continues to be guidance
support from high-res models for scattered snow showers
along/behind the frontal zone late this evening into the
overnight hours, with lake to 850 mb delta-Ts around 15/16C and
equilibrium heights around 6 kft. This may support some
scattered lake-induced snow showers overnight as the mid-level
trough axis passes overhead. While blended pop guidance isn`t
too excited, did add some slight chance (~20%) pops over the
lake and adjacent counties of northeast IL/northwest IN for the
overnight hours as well as some patchy trace to 0.1 accumulation
amounts. We`ll have to keep an eye on trends later
today/tonight in case these snow showers end up being more
robust. Low-level winds ramp down quickly Tuesday morning as
surface high pressure builds in from the northwest, though a
weak convergence axis is progged to linger into the northwest IN
shore during the morning, thus scattered snow showers would
likely persist into early Tuesday there before dissipating.

Temperatures should fall off quickly Tuesday evening, dipping
into the 20s again over far northeast IL (especially northern
Chicago suburbs) as the center of the surface high shifts just
to our east across the Great Lakes. Surface winds back south-
southeast overnight however as the high drifts away, and warm
advection flow ramps up downstream of an upper trough over the
Plains. This, in addition to increasing cloud cover, should
produce slowly rising temperatures into the low-mid 30s
overnight. There also remains decent model and ensemble
agreement in resulting moist isentropic ascent and frontogenetic
forcing within the northward advancing mid-level baroclinic
zone to result in development of light snow (potentially
changing to rain as the column warms/moistens) overnight,
primarily across the northwest half or so (generally northwest
of the I-55 corridor). As the previous discussion indicated,
NBM pops can be underdone in these lighter QPF scenarios, but
did come in slightly higher than previous runs. Also can`t rule
out a brief period of freezing rain as the column warms, though
surface temps will also be rising with time as well and expect
any FZRA would be short-lived.

Any lingering precipitation should lift north of the cwa early
Wednesday morning, with a dry, breezy (windy?) and much warmer
day in store. NBM blended wind guidance currently tops out near
35 mph, though higher gusts around 40 mph would be possible if
cloud cover clears out sufficiently in the afternoon. Current
forecast highs in the mid-upper 60s could also be a little
underdone if we were to mix more deeply with more sunshine.

Shower chances then return to the area Wednesday night and
Thursday, as a deep upper trough lifts across the upper Midwest
and trails a cold front into the region during the
Thursday/Thursday night period. Can`t rule out some embedded
thunderstorms, though instability continues to look fairly muted
within the relatively narrow moist axis ahead of the front,
with guidance maintaining greater SB/MUCAPE values back across
the Plains and lower Missouri Valley. Details remain somewhat
unclear later in the forecast period, as surface high pressure
eventually builds into the upper Midwest while the
aforementioned cold front stalls across our south of our area.
If the front stalls nearby, additional short waves transiting
the baroclinic zone could support additional rounds of showers
and possibly thunderstorms Friday into the weekend. If the high
builds in more strongly, the front could end up far enough south
of the forecast area for a period of dry weather early in the
weekend. In either case, global ensembles continue to suggest an
active weather pattern persists early next week.

Ratzer

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1222 PM CDT Mon Apr 6 2026

VFR conditions expected through the TAF cycle. A SCT v BKN VFR
stratocumulus deck is expected into this evening with bases
above FL040. Gusty northwest winds through early this evening
will veer to north-northeast tonight.

- Izzi

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 1 PM CDT Tuesday for the IL
     nearshore waters.

     Small Craft Advisory until 4 PM CDT Tuesday for the IN
     nearshore waters.

&&

$$

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